Lt. Gen. Peter Devlin, Commander of the Canadian Army, speaks to attendees of news conference on Camp Lejeune, in Jacksonville, N.C., Friday Jan. 6. John Althouse

A major shakeup is in the offing amid the senior ranks of the Canadian military, one that appears to give the new chief of defence staff an open field to implement the Harper government's long-planned defence reforms.

The country's deputy top commander, Vice-Admiral Bruce Donaldson, will retire in the coming months, along with the heads of the army and navy.

An internal notice posted late Tuesday at National Defence headquarters announced the changes, which come as the military struggles to deal with pending budget cuts and a massive internal reorganization.

Donaldson will be replaced as vice chief of defence staff by Lt.-Gen. Guy Thibault, a career army officer who recently served in Washington.

The commander of the Canadian Army, Lt.-Gen. Peter Devlin, a veteran of Afghanistan, is also leaving, to be replaced by Lt.-Gen. J.M.M. Hainse, who currently serves as deputy commander of NATO's joint force command in Naples.

Hainse will be replaced overseas by Maj.-Gen. Jon Vance, the country's most experienced battlefield commander in Kandahar.

Vice-Admiral Paul Maddison, who only assumed command of the navy in July 2011, also announced his retirement and will be replaced by Rear Admiral Mark Norman.

The changes of command, to be staggered over the next few months, follow the departure last fall of longtime chief of defence staff, retired general Walt Natynczyk, and the former commander of the air force, retired lieutenant-general Andre DesChamp.

The latest changes mean that within the space of a few months the entire senior leadership of the military will have changed, said Douglas Bland, a defence analyst at Queen's University, in Kingston, Ont.

"I think a lot of people, myself and others on the outside, expected many of these officers were going to guide the Forces through the post-Afghan period," said Bland, the chair of the university's defence management studies program.

Significant among the changes is the retirement of Maj.-Gen. Al Howard, who has been in charge of the defence renewal team. He'll be replaced by Rear Admiral Andrew Smith, the current chief of military personnel.

Bland said some officers were due to retire, but the clearing of the deck is significant at this point because some of those departing were apparently unhappy with the Harper government's transformation plans, as articulated in a report almost two years ago by another retired officer, former lieutenant-general Andrew Leslie.